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Diffstat (limited to 'arch/powerpc/net/bpf_jit.h')
| -rw-r--r-- | arch/powerpc/net/bpf_jit.h | 185 |
1 files changed, 185 insertions, 0 deletions
diff --git a/arch/powerpc/net/bpf_jit.h b/arch/powerpc/net/bpf_jit.h new file mode 100644 index 000000000..72b7bb34f --- /dev/null +++ b/arch/powerpc/net/bpf_jit.h @@ -0,0 +1,185 @@ +/* SPDX-License-Identifier: GPL-2.0-only */ +/* + * bpf_jit.h: BPF JIT compiler for PPC + * + * Copyright 2011 Matt Evans <matt@ozlabs.org>, IBM Corporation + * 2016 Naveen N. Rao <naveen.n.rao@linux.vnet.ibm.com> + */ +#ifndef _BPF_JIT_H +#define _BPF_JIT_H + +#ifndef __ASSEMBLY__ + +#include <asm/types.h> +#include <asm/ppc-opcode.h> + +#ifdef CONFIG_PPC64_ELF_ABI_V1 +#define FUNCTION_DESCR_SIZE 24 +#else +#define FUNCTION_DESCR_SIZE 0 +#endif + +#define CTX_NIA(ctx) ((unsigned long)ctx->idx * 4) + +#define PLANT_INSTR(d, idx, instr) \ + do { if (d) { (d)[idx] = instr; } idx++; } while (0) +#define EMIT(instr) PLANT_INSTR(image, ctx->idx, instr) + +/* Long jump; (unconditional 'branch') */ +#define PPC_JMP(dest) \ + do { \ + long offset = (long)(dest) - CTX_NIA(ctx); \ + if ((dest) != 0 && !is_offset_in_branch_range(offset)) { \ + pr_err_ratelimited("Branch offset 0x%lx (@%u) out of range\n", offset, ctx->idx); \ + return -ERANGE; \ + } \ + EMIT(PPC_RAW_BRANCH(offset)); \ + } while (0) + +/* bl (unconditional 'branch' with link) */ +#define PPC_BL(dest) EMIT(PPC_RAW_BL((dest) - (unsigned long)(image + ctx->idx))) + +/* "cond" here covers BO:BI fields. */ +#define PPC_BCC_SHORT(cond, dest) \ + do { \ + long offset = (long)(dest) - CTX_NIA(ctx); \ + if ((dest) != 0 && !is_offset_in_cond_branch_range(offset)) { \ + pr_err_ratelimited("Conditional branch offset 0x%lx (@%u) out of range\n", offset, ctx->idx); \ + return -ERANGE; \ + } \ + EMIT(PPC_INST_BRANCH_COND | (((cond) & 0x3ff) << 16) | (offset & 0xfffc)); \ + } while (0) + +/* Sign-extended 32-bit immediate load */ +#define PPC_LI32(d, i) do { \ + if ((int)(uintptr_t)(i) >= -32768 && \ + (int)(uintptr_t)(i) < 32768) \ + EMIT(PPC_RAW_LI(d, i)); \ + else { \ + EMIT(PPC_RAW_LIS(d, IMM_H(i))); \ + if (IMM_L(i)) \ + EMIT(PPC_RAW_ORI(d, d, IMM_L(i))); \ + } } while(0) + +#ifdef CONFIG_PPC64 +#define PPC_LI64(d, i) do { \ + if ((long)(i) >= -2147483648 && \ + (long)(i) < 2147483648) \ + PPC_LI32(d, i); \ + else { \ + if (!((uintptr_t)(i) & 0xffff800000000000ULL)) \ + EMIT(PPC_RAW_LI(d, ((uintptr_t)(i) >> 32) & \ + 0xffff)); \ + else { \ + EMIT(PPC_RAW_LIS(d, ((uintptr_t)(i) >> 48))); \ + if ((uintptr_t)(i) & 0x0000ffff00000000ULL) \ + EMIT(PPC_RAW_ORI(d, d, \ + ((uintptr_t)(i) >> 32) & 0xffff)); \ + } \ + EMIT(PPC_RAW_SLDI(d, d, 32)); \ + if ((uintptr_t)(i) & 0x00000000ffff0000ULL) \ + EMIT(PPC_RAW_ORIS(d, d, \ + ((uintptr_t)(i) >> 16) & 0xffff)); \ + if ((uintptr_t)(i) & 0x000000000000ffffULL) \ + EMIT(PPC_RAW_ORI(d, d, (uintptr_t)(i) & \ + 0xffff)); \ + } } while (0) +#endif + +/* + * The fly in the ointment of code size changing from pass to pass is + * avoided by padding the short branch case with a NOP. If code size differs + * with different branch reaches we will have the issue of code moving from + * one pass to the next and will need a few passes to converge on a stable + * state. + */ +#define PPC_BCC(cond, dest) do { \ + if (is_offset_in_cond_branch_range((long)(dest) - CTX_NIA(ctx))) { \ + PPC_BCC_SHORT(cond, dest); \ + EMIT(PPC_RAW_NOP()); \ + } else { \ + /* Flip the 'T or F' bit to invert comparison */ \ + PPC_BCC_SHORT(cond ^ COND_CMP_TRUE, CTX_NIA(ctx) + 2*4); \ + PPC_JMP(dest); \ + } } while(0) + +/* To create a branch condition, select a bit of cr0... */ +#define CR0_LT 0 +#define CR0_GT 1 +#define CR0_EQ 2 +/* ...and modify BO[3] */ +#define COND_CMP_TRUE 0x100 +#define COND_CMP_FALSE 0x000 +/* Together, they make all required comparisons: */ +#define COND_GT (CR0_GT | COND_CMP_TRUE) +#define COND_GE (CR0_LT | COND_CMP_FALSE) +#define COND_EQ (CR0_EQ | COND_CMP_TRUE) +#define COND_NE (CR0_EQ | COND_CMP_FALSE) +#define COND_LT (CR0_LT | COND_CMP_TRUE) +#define COND_LE (CR0_GT | COND_CMP_FALSE) + +#define SEEN_FUNC 0x20000000 /* might call external helpers */ +#define SEEN_TAILCALL 0x40000000 /* uses tail calls */ + +struct codegen_context { + /* + * This is used to track register usage as well + * as calls to external helpers. + * - register usage is tracked with corresponding + * bits (r3-r31) + * - rest of the bits can be used to track other + * things -- for now, we use bits 0 to 2 + * encoded in SEEN_* macros above + */ + unsigned int seen; + unsigned int idx; + unsigned int stack_size; + int b2p[MAX_BPF_JIT_REG + 2]; + unsigned int exentry_idx; + unsigned int alt_exit_addr; +}; + +#define bpf_to_ppc(r) (ctx->b2p[r]) + +#ifdef CONFIG_PPC32 +#define BPF_FIXUP_LEN 3 /* Three instructions => 12 bytes */ +#else +#define BPF_FIXUP_LEN 2 /* Two instructions => 8 bytes */ +#endif + +static inline void bpf_flush_icache(void *start, void *end) +{ + smp_wmb(); /* smp write barrier */ + flush_icache_range((unsigned long)start, (unsigned long)end); +} + +static inline bool bpf_is_seen_register(struct codegen_context *ctx, int i) +{ + return ctx->seen & (1 << (31 - i)); +} + +static inline void bpf_set_seen_register(struct codegen_context *ctx, int i) +{ + ctx->seen |= 1 << (31 - i); +} + +static inline void bpf_clear_seen_register(struct codegen_context *ctx, int i) +{ + ctx->seen &= ~(1 << (31 - i)); +} + +void bpf_jit_init_reg_mapping(struct codegen_context *ctx); +int bpf_jit_emit_func_call_rel(u32 *image, struct codegen_context *ctx, u64 func); +int bpf_jit_build_body(struct bpf_prog *fp, u32 *image, struct codegen_context *ctx, + u32 *addrs, int pass, bool extra_pass); +void bpf_jit_build_prologue(u32 *image, struct codegen_context *ctx); +void bpf_jit_build_epilogue(u32 *image, struct codegen_context *ctx); +void bpf_jit_realloc_regs(struct codegen_context *ctx); +int bpf_jit_emit_exit_insn(u32 *image, struct codegen_context *ctx, int tmp_reg, long exit_addr); + +int bpf_add_extable_entry(struct bpf_prog *fp, u32 *image, int pass, struct codegen_context *ctx, + int insn_idx, int jmp_off, int dst_reg); + +#endif + +#endif |